Make sure you swap in a fuel pump accentric if you're going to run a mechanical fuel pump. Everything else just needs to be "Mustang specific" like the oil pan and water pump. As far as the block itself goes its the same thing.
I think you should take a look at some of the how-to threads that have already been done here. This will give you an idea of what it takes. It's hard to answer such an open-ended question.
Also, be sure you have the right dizzy gear for that roller cam given the dizzy out of the Explorer will not work with the carb setup. You either need a dizzy from a 85 carb roller or possibly just change the gears out with yours.